The shaft has a tube (17) and at least one pin with an insertion (13) and connection (14) sections. The insertion section fits in an accommodation bore (18) in one end of the tube and the connection section connects with the synchronous pivot. The tube has a hardened outer surface (20). The tube has a tubular tension ring (21), the axial length (L) of which is longer relative to the longitudinal axis (Y) of the pivot than the covering length (X) of the insertion section. The tension ring extends over the ends of the insertion section when inserted. The outer surface of the tube has a hardness of between 50 to 62 HRC, but preferably 55 to 60 HRC.
